Expanding fly cutter



July 3, 1923.. 1,460,427 :J. P. MILLS v I EXPANDING FLY CUTTER Fil edFeb, 24. 1920 INVENTOR.

JAMES P. MILLS.

A TTORNEY.

Patented July 3, 1923.

UNITED sr T's-s1- PATE QEE CE JAMES P. MILLS, or nnfrrtorr, MIGI-IIGEAN,ASSIGNOR' To-oouTINEN'rAL-Morons-con ron a'rrou; or nnrajorr, MICHIGAN,AoonroaATIou or VIRGINIA; I

- EXPANDING FLY CUTTER.

I v..A plication filed February 2 192:9. Serialjll'o. 360962.

ToaZZ whomit may concern; f; j -'Be it known that I, JAMEslVlrLns, acitizenof, the-United Statesj res ding at Detroit, inthecounty of lVayneand-sea 5 of Michigan have invented a new' and useful Improvement inExpanding ters, of .which the following s a specificati'on. v

. My invention relates'to an in rprovedform of expanding fly cutter foruse where a shell cutter must be employed asdistinguls'hed from a solidcutter, and it is a further feature of my invention to provide suchadevice with improved means of accurately grinding the fly cutter to adesired cutting radius. 1 I 1 My improved construction is particularlyapplicable for use in connection Wltllltl1 finishingof' bearings orseats for bearings 20 where a central boreis finished by the sameoperation that outside bores of lesser diameter are finished by means ofthe same boring bar.

My invention will best be understood by showing a preferred embodimentthereof in which- I Fig. 1 shows the device in longitudmal sectionalview, 1 i

Fig. 2 is an end view of the parts shown in Fig. 1,

Fig. 3 is a plan view of one of the cutters employed, and V I I Fig. 4:shows the cutter in side elevation.

Similar numerals refer to similar parts throughout the several views.

As shown inFig. 1 my device consists of a sleeve 10 having on oppositesidesthereof, inclined grooves 11 and 12 for receiving the bars 13 and14 respectively, said bars hav ing inclined inner faces correspondingwith the lnclination of the bottoms of thegrooves.

The ends of the bars 13 and 14 are beveled to be engaged by internallythreaded collars 15 and 16 which engage corresponding threads formed onthe ends of the shell 10.

The collars 15 and 16 are held in any desired adjustment by the lockingcollars 17" and 18 respectively which. are internally threaded and fiton the threads on the ends of the shell 10. One of the bars-13 and 14has a cutter 19 or 20 projecting outwardly from it. this cutterbeingpreferably inclined somewhat to the axis of the shell 10 as'indicatedfor the cutter 19 in Figs. 3 and 4.

' reference to the accompanying drawings Pins 21 project inwardly-fromtheshelfll l toengage a driying' baron which thejs'hell'" may bemountedjw-hen the'cutter is' intuse.

Inf preparing'm'yj improved I euttencdn struction for 7 use; the shell510" is mounted on the arbor-of a 1 grinding machine, theahre dedcollars are adjusted so thatthe "cutter19 and the projection 20'b0thproject" slightly v beyond required s s ad u idr the jection 20' areground, by; g qmtio Ofthe arbor Carrying the ll 10 until the diam- 7 teroyer the cutter "19 and 'the projection 20 is exactly thedesi'redcutting diameter 'for. I

'70 certain operations which are contemplated the present inventiom anycutter must be emp'loyed to give good. results' as", distin- 1 guishedfrom a cutterihaving a pluralityof; cutting edges and to produce" thiseoa'strue the tool. As is well knownlin' the 1' art; .for

tion, after the, tool has been ground as described, the projection 20,has an additional amount ground from its edge which is just I sufficientto clear the depth of cut f the cutter. This it will be readily seendoes not disturb the cutting radius of the cutter, and the dev ce may beplaced" on a boring bar and used with the certainty that the bored holewillhave the desired diameter. When it 1s necessary to sharpen thecutter sthe threaded collars are released and moved I along the sleeve10 so that the bars. 13 and 14 are moved outwardly enough'togpermittheir outeredges to be ground off to bring. the cutter and theprojectionagain togthe desired radius.

It will be understood'that the boring bar supporting the cutterforming'the subject;

matter of this invention, particularly. where I the boring bar is usedas above referred to, to bore a plurality of bearings or seats forbearings by the same operation andby the same boring bar, is preferablysupported at I both ends to prevent vibration and insure s mo accuratework. In the event o-f'bo'ring several bearings or seats for bearings bythe same operation; particularly where the bear-. 5

ings or seats for bearings are of different diameter, as for example thecrank shaft bearings in the, crank case of aninternal combustion motor;a separate cutteriis used for'each bearing :or bearing seatj'Yt-he con-'1 struction of boring bar preferably permitting ready engagement of theborlng bar,

by the pins 21 of the cutter and ready re movability of the-cutter fromthe boring bar.

From the above it will be understood that by myinvention ready means areprovided for accurately grinding a fly cutter of the type described tosize, and furthermore that by my construction all of the parts may beused repeatedly by moving a tubular cutter has its cutting portionformed integrally with its shell.

While I have shown my invention in the particular embodiment abovedescribed, I :do nothowever limit myself to this exact construction incarrying out my invention, asI may employ equivalents thereof known tothe art at the time of the filing of this application without departingfrom the scope of the appended claims.

What I claim is:

1. A fly cutter comprising a cylindrical shell, a pair of longitudinallyextending bars adj ustably secured at diametrically o-p- .posite sidesof said shell, a cutting blade carried by and extending radially'fromone of said bars, and a gauging projection carried by and extendingradially from the other of said bars, said gauging projection, when thecutter is ready for use, being reduced to slightly less radius than saidcutting blade, whereby said projection clears the finished portion ofthe bore.

The hereindescribed method of accurately gauging the cutting radius of arotary cutter having but asingle cutting blade projec'ting from itsperiphery, which comprises providing a radial projection on said cutterat a point diametrically opposite said blade, grinding the ends of saidblade and projection to an equal radius and until their overall diameteris equal to that of the bore desired, and then further grinding off theend of said projection until its radius is slightly less than that ofthe blade, whereby, in operation, when the cutter is mounted on a rigidarbor, the projection does not engage the Work.

In witness whereof, I hereunto subscribe my name this 2nd day ofFebruary, A. D. 1920. 1

JAMES P. MILLS.

